(a) Field of the Invention
The present invention relates to a particulate matter sensor.
(b) Description of the Related Art
Typically, enforcement of vehicle exhaust gas discharge regulations has resulted in restriction and reduction of permissible levels of exhaust gas discharge. For example, as a representative reference, an allowance value of nitrogen oxide (NOx), was decreased to about 0.4 g/kWh. Generally, a diesel engine generates exhaust flow that includes variable amounts of particulate matter (PM). Accordingly, to comply with more stringent requirement regulations, a vehicle that includes a diesel engine requires inclusion of a diesel particulate filter Diesel Particulate Filter (DPF) that reduces the exhaust flow and On-Board Diagnostics (OBD) that detects a malfunction of the DPF.
An OBD sensor is a sensor configured to detect a failure of a vehicle component that has an influence on exhaust gas discharge and configured to notify a user when a DPF has failed. For example, the OBD sensor includes a broadband temperature sensor, a differential pressure sensor, an oxygen sensor, a NOx sensor, and a Particulate Matter (PM) sensor. A recommended exhaust amount of a PM is typically less than about 0.009 g/km. Therefore, it is difficult to perform PM monitoring to satisfy the requirement with a differential pressure sensor that has already been utilized to monitor a PM exhaust amount. Accordingly, a PM sensor that more accurately measures a PM exhaust amount is required.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.